Apparatus for finishing surfaces



June 26, 1951 w. l. KNAPP APPARATUS FOR FINISHING SURFACES 5Sheets-Sheet 1 Filed March 18, 1946 INVENTOR WALTER I. KNAPP ATTORN EYSmy a June 26, 1951 W. l. KNAPP APPARATUS FOR FINISHING SURFAC 5Sheets-Sheet 2 Filed March 18, 1946 FTMZnu/n' ATTORNEYS INVENTOR WALTERI. KNAPP 9y J June 26, 1951 W. l. KNAPP APPARATUS FOR FINISHING SURFACESFiled March 18, 1946 5 Sheets-Sheet 5 FIG.3

INVENTOR WALTER I. KNAPP ATTORNEYS INVENI'OR WALTER I. KNAPP ATTORNEYS 5Sheets-Sheet 4 W I KNAPP APPARATUS FOR FINISHING SURFACES June 26, 1951Filed March June 26, 1951 w. l. KNAPP 2,558,300

APPARATUS FOR FINISHING SURFACES Filed March 18, 1946 5 Sheets-Sheet 5INVENTOR WALTER I KNAPP ATTORNEYS .skillets.

Patented June 26, 1951 UNITED APPARATUS FOR FINISHING SURFACES Walter I.Knapp, Detroit, Mich., assignor to Frederic B. Stevens, 1110., Detroit,Mich., a cor:

poration of Michigan Application March 18, 1946, Serial No. 655,306

7 .Claims. 1

This invention relates to apparatus for finishins utensils or vesselssuch as pots, pans and More particularly, this invention refers to anautomatic machine for finishing the surfaces of cast, draw-n or spunutensils such as aluminum, copper or iron pans or skillets.

In the manufacturing of utensils a final .step is that of finishing thesurface. This finish is usually obtained by spinning the utensil in achuck and manualh abrading the surface with .a piece .of emery cloth orsimilar flexible cutting medium. In order to obtain the uniform and neatappearing results required, considerable skill must be employed inmanipulating the abra sive member. In addition, the manual processing ofthe utensils is slow and the results at best are variable.

The object of the present invention is to pro vide a machine formechanically finishing the insides Qf utensils and to obtain a resultequal or better than is possible by manual means.

Another object is to provide such a machine which will be fullyautomatic.

Still another object is to provide an automatic machine for applying thefinal finish to the insides of utensils which includes a turret forholding the workpieces.

Still another object is to provide a machine according to the foregoingobjects which is adjustable for different types and sizes of utensils.

Another object is to provide an apparatus for finishing the insides ofutensils by abrading such that an improved product results and such thatthe rate of production is substantially increased.

It is also an object to provide, in connection with a machine accordingto the foregoing objects, safety limits by means of which the machine ishalted suddenly in case of breakage, misadjustment orimproper operation.

These and other objects and advantages will become more apparent uponreference to the following description and the accompanying drawings inwhich:

Figure 1 is a plan view of a machine constructed according to thisinvention;

Figure 2 is a side View of the machine looking in the direction of thearrow 2 on Figure 1 Figure 3 is a section taken substantially along theline 3-3 of Figure 2;

Figure 4 is a view taken substantially along the line 4-4 of Figure 3showing one of the :adi-ustments of the machine;

Figure 5 is :an enlarged view of the low-er end of the abrading arm inoperative position;

Figure 6 is a section on the line 6-6 of Figure 5 showing one of thesafety limits;

Figure -7 is a view looking substantially in the direction of the arrows1---] on Figure 5;

Figure 8 is a section taken on the line 8-8 of Figure 5 showing thecontour of the shoe at the end of the abrading arm;

Figure 9 is a section taken substantially along the line 9--9 of Figure2 and shows the connections to the vacuum chuck in the turret;

Figures 10, 11 and 12 are fragmentary views showing the abrading arm andthe actuating mechanism therefor in different operative positions duringa cycle; and

Figure '13 is a wiring diagram for controlling the actuation of theabrading arm and theturret indexing motors.

General arrangement form of a flexible tape such as emery cloth and of atexture of from number to 100. When tape is used as the .abradingmedium, a mechanism is provided for Shifting the tape a pred,e terminedamount for each cycle so that a fresh abrading surface is presented toeach utensil.

For actuating the abrading arm there is provided cam and linkagemechanisms which are driven in rotation by .a suitable motor means.

The cams and linkage drive the abrading arm so that the tip thereoffollows the surface of the utensil being finished and the cam may b soshaped and the links so proportioned that the contour of any utensil maybe followed'with great exactness.

A uniform pressure on the utensil is obtained by suitable yielding meanswhich continuously urge the abrading tip of the abrad-ing arm intoengagement with the Surface of the utensil.

Suitable means such as limit switches are located on the abrading arm sothat improper operation of the machine, breakage :of the abrasive tape,or maladjustment of the machine, will immediately bring the machine to ahalt, and :main- 3 tain it in a halted position until the trouble hasbeen cleared.

In addition to the cam and linkage which may be replaced to vary thepath through which the abrading tip passes, the machine includes meansfor raising and lowering the abrading mechanism as a unit, for moving ittoward or away from the working station as a unit, or for bodily tiltingthe abrading mechanism.

Structural arrangement 7 Referring to the drawings and particularly toFigures 1 through 5, a machine according to this invention comprises abed. II which adjustably supports a foot member I2 having, in turn,adjustably connected therewith the column I4.

The column It carries a table It towhich is pivoted, as at IS, a plate23. In Figures 3 and 4 it will be noted that the table I6 is verticallyadjustable on the column It by the rack 22 on the latter and the gear 2carried by the former. The ,gear 24 is connected through the shaft 26,the self-locking worm mechanism 36 and the shaft 28 with a manualadjusting means at 32 which is operable to raise and lower the table Iton the column M. The plate 28 is abutted by a screw 34 which passesthrough the table It and which is selectively operable to tilt the plateabout its pivot I8 to any desired'degree of angularity.

The plate 23 has secured thereto the upstanding plate 36 upon which iscarried the abrading mechanism generally indicated at 33. The abradingmechanism consists of an arm 46) which is slidable through a bearingblock G2, which has at its lower end the abrading tip generallyindicated at 44 and which is pivoted at its upper end at 46 to an arm38. The arm 48 is pivoted between its ends as at 59 to the plate 36 andhas a pivot 52 at its other end.

Pivoted to the arm as at 52 is another arm or link 54 which has a slot56 therein which slides over a shaft 58 extending through the plate 36.Optionally the shaft 58 may have a roller or other suitable journallingmeans whereby the reciprocation of the link 54 relative thereto isfacilitated.

The shaft 58 has connected therewith a cam 66 which has a cam track 62formed into the face 7 thereof. The cam track 62 receives a roller orfollower 64 which is secured to the arm 54. As

the cam rotates the arm 5:3 is reciprocated and has its end pivotallyconnected as at 68 with a lug outstanding from the bearing block 62. Theseveral links may comprise a plurality of points 'for receiving theseveral pivots and the cam 50 may be replaced by another with a modifiedcam track for the purpose of varying the path through which the arm 40passes. The particular arrangement shown in the drawings is for th purpose of finishing the inside of a pan having a flat bottom and verticalside walls.

For driving the cam 68 in rotation, the shaft 58 is connected throughthe reduction gearing 59 with the output shaft 6| of a speed reducingtransmission 63. The input shaft of the transmission 63 is connected tobe driven by the electric motor 65. The motor and speed reducer aremounted on the plate 2!! in any suitable manner.

The utensil to be finished is indicated at In in Figures 1, 2, and 5 andwill be seen to be supported in a chuck 12 which has a plurality ofpassages I4 and ports I6 therein. The passag 14 lead to a centralpassage I3 which passes vertically downwardly through the spindle 80 ofthe chuck to a plurality of substantially radial passageways whichterminate in a circumferential groove about the said spindle. Thisgroove is indicated at 82 and is in communication with a passage 84 inthe turret plate 86 which supports the several chucks.

The turret plate 86 is carried on a central column 88 and is journalledin the upstanding portion 90 of the machine bed ID. For clamping theutensil in the chuck at the working station, there is provided a passage92 in the portion 90 which is connected at one end with a vacuum conduit94 and, at the other end, with a recess 96 which registers with thepassage 8 when the turret brings the chuck into working position. Theturret may be indexed by any suitable means but it is preferred toemploy the Geneva mechanism consisting of the slotted plate 98' which isengaged by the rotary plate IQ!) having the indexing pinIIlZ. The platein may be driven by any suitable means but, for the purposes ofillustration, the motive power is shown in the drawings as comprising anelectric motor I54.

The slotted plate 98 and the plate IOEl carrying the pin I82 operate inthe manner of 'a regular Geneva mechanism, the pin it! engaging one ofthe slots of the plate 98 as the plate I00 rotates and indexing theplate 98 through 90 degrees to bring another workpiece into the workstation. The raised part in the center of the plate H30 acts as a key toretain the plate 98 in its indexed position. It will be understood thatthe plate I00 could be operated continuously or intermittently, asdesired, depending on the rapidity with which it is wished to index theturret 86.

For rotating the chuck 12 which is in working position, the spindle 8|!thereof is coupled with the drive shaft of a motor I04 which is carriedon a plate I08 attached to the turret plate 86. The motor I04 is adaptedfor energization when the chuck to which it is attached is moved intoworking position by means of the brush mechanism and slip ring indicatedat I98.

Returning to the abrading arm, and particularly to the abrading tip Mi,this portion of the mechanism is more clearly seen in Figure 5. The arm4!] comprises a rectangular or cylindrical tube having connectedtherewith a plate III]. Adjustably mounted within the plate I H] is arod I I2 that extends downwardly and has a head H4 thereon. Slidablymounted in the end of the arm 4%] is a framework H6 which carries theabrading tip mechanism which has been indicated generally at 44. Thesaid mechanism is urged downwardly by a spring H8 which bears between aplate I2!) secured to the framework I I6 and a plate I22 which isadjustably supported in the arm M) as by the screws and wing nuts I24which extend through the slots I26 in the arm The framework H6 extendsdownwardly from the arm 40 and carries a channel portion I28 which hasjournaled in the lowermost end thereof a roller I30 of some suitablyresilient material such as felt. The roller I30 is preferably curved tohave a somewhat greater curvature than the utensil being finished as isindicated in Figure 8.

Passing around the roller I3!) is a flexible tape I32 which is coatedwith emery or a similar abrasive and preferably of about the texture ofNo. to No. 100 emery. The tape I32 is paid off from a reel I34 carriedbetween a pair of arms which extend laterally from the framework I I6.A'tension spring I36 connected between the reel I34 and the supportingbracket therefor continuously urges the said reel in its taking updirection with a substantially constant torque, whereby a substantiallypredetermined tension is maintained on the tape I32. After the tapepasses around the roller I33, it is attached toa takeup reel 138 that isalso carried in a pair of arms extending from the framework H6. The reel138 has connected therewith a ratchet wheel M0 which is engaged by aspring pressed pawl M2. A second pawl I44 is urged away from the saidwheel by a spring I46. The tape is guided between the reels by thechannel guards I 33 and I35 and passes over a roller I31 immediatelybefore passing to the takeup reel.

As will become apparent hereinafter when the arm 16 is moved upwardlyand out of the utensil 16, the upper end of the pawl I44 strokes the armI4 8 carried on the bearing block 42 and actuates the said pawl to indexthe reel I38 to take up the predetermined amount of the tape I32. Thisautomatically provides a fresh abrasive surface to be presented to thenext utensil to be finished.

The spring 8 urges the abrading tip against "the bottom of the utensilwith a predetermined thrust and, when the arm 6!! is moved to presentthe abrad'ing tip to the side of the utensil, the

hinge I56 and spring I52provide tensioningmeans for urging the abradingtip laterally against the side of the utensil with a substantially equalthrust.

In connection with Figure 2, Figures 10, '11 and I12, illustrate thecam, links and abrading tip in several of its operative positions duringa work cycle. Figure 2, the abrading tip is resting .in the center ofthe bottom of the utensil. In Figure 10, the cam 66 has rotated about 60and the abrading tip has reached the corner of the utensil. It will benoted that the roller I30 has a radius not greater, and preferablysmaller, than the radius of theflllet in the corner of the utensil. InFigure 11, the cam has rotated until the abrading tip has reached theupper edge of the utensil side wall, and in Figure 12, the cam is turnedto bring the abrading tip substantially vertically above the startingposition indicated in Figure 2.

For actuating the cam driving motor 65 and the turret indexing motorI54, there is provided the electrical circuit illustrated in Figure 13.In this figure, the power lines are indicated at :LI

and L2 and therebetween are connected the sevit will be seen to comprisemating contacts carl P 'ried on the framework H6. The framework isdivided between the contacts and there is a hinge 162 which permits thecontacts to open when the lower portion of the framework H6 .is pivotedrelative to the upper portion. The lower portion of the framework isyieldably retained in position by the spring and detent mechanismindicated at I64.

The switch I58 is a sensitive limit switch and is carried in theU-shaped member I28. The

6 switch I58 is normally held closed by its actnat .ing roller I66 whichis engaged by the tape I32. When the tape breaks, runs off the payoffreel, or loses tension for any other reason, the switch I58 opens tohalt the machine.

The switch I60 is a manually operated on and off switch and ispreferably carried on the table I6 or in any'other position convenientto the machine operator.

The side of the switch I58 opposite the line LI is connected with a lineI68 which, in turn, is connected through the limit switch LSI and thecontactor coil B with the line L2. The limit switch .LS'I is carried onthe machine bed and is actuated into closed position by the cams I10carried on the turret plate 86. The contactor coil B has the normallyopen blade BI which is in series with the cam motor 65 between the linesI68 and L2. The blade BI is bypassed by the normally closed blade AI ofthe contactor A which is in series between the lines L2 and I68 with thenormally open limit switch LS3.

The switch LS3 is preferably carried on the bearing block 42 and isadapted for being actuated into closed position by an adjustableabutment I12 connected with the arm 40. When the arm 40 is moved to itsFigure 12 position, the switch LS3 is actuated to its closed position toenergize the contactor coil A and to open the blade AI thereof.

Connected between the lines I68 and L2 is a contactor coil C in serieswith a selector switch I14, and a normally open limit switch LS2. Thelimit switch LS2 is bypassed by the push button station I16 and aholding circuit consisting of the normally open blade C2 and thenormally closed limit switch LS4. The limit switch LS4 is carried on themachine bed and is actuated into opened position temporarily by the camsI10 as the turret rotates. The limit switch LS2 is preferably supportedon the bearing block 42 and is temporarily actuated into closed positionas the arm '40 moves upwardly and toward its Figure 12 position. Theselector switch I16 may be closed as indicated for full automaticoperation of the machine and opened for semi-automatic to initiate a newcycle. When the switch I14 is opened, the push button I16 must be closedto inaugurate each new cycle.

The contactor coil 0 has the normally open blade .CI in series with theturret indexing motor I54 and, when the coil C is energized, the indexmotor operates to rotate the turret. The blade CI is bypassed by thenormally closed blade B2 of the coil B.

In order quickly to halt the operation 01" the machine in the event thateither of the emer gency limit switches or the hand switch I56 isopened, the motors may be provided with a magnetic brak construction,one of which is shown in association with cam driving motor 65. Thebrake construction. consists of a drum I18carried on the motor shaft anda pair of shoes I86 surrounding the drum and urged away from the saiddrum by a spring I 82. A solenoid and armature indicated at I 84 isadapted, when energized, to actuate the brake mechanism and there bysuddenly to halt the rotation of the drive motor. For actuating thesolenoid I84, there is provided in a series therewith the normallyclosedblade D3 of the contactcr coil D. The solenoid I84 and the blade D! areconnected between the lines LI and L2 while the coil D is connectedbetween the lines L2 and I58. When any of the switches I56, 158 or 166are opened, the coil ,D

Operation In operation, a pan-shaped workpiece, such as a kitchenutensil, is placed in the turret and indexed into position under theabrading station. When the turret reaches working position, the switchLSI is actuated to energize the coil B thereby to close the blades Blthereof and to open the blades B2 thereof. Opening of the blades B2deenergizes the turret motor I54 and closing of the blades Bl energizesthe cam motor 65.

Energization of the cam'motor 65 drives the abrading arm through itspath to finish the "interior of the utensil Hi, the said utensil beingdriven in rotation by its supporting chuck 12. When the abrading arm hasfinished its working stroke and is approaching its Figure 12 position,it actuates the limit switch LS2 into closed position. Closing of LS2,if switch H4 is closed, energizes the coil C which is held by theholding circuit including the blade C2 and the switch LS4.

Energization of C closes the blade Cl and ener gizes the turret indexingmotor. The "turret therefore commences its indexing movement. Theabrading arm 59 continues its upward movement until it passes the limitswitch LS2 and strikes the limit switch LS3. Closure of the limit switchLS3 energizes the contactor coil A to open 7 the blade A2 thereofthereby to deenergize the cam motor 65. At this time, the turret hasindexed to the position where the cam I70 permits the limit switch LSIto open so that the coil B is deenergized and the blade Bl thereof isopened and blade B2 thereof is closed.

The cam motor thus remains deenergized. As the indexing movement of theturret progresses, one of the cams ll!) opens t -e limit switch LS4 anddeenergizes the coil C. Deenergization of C opens the blade Cl thereofbut the indexing motor Hill continues to operate because of the blade B2which is closed.

When the turret has indexed to the point where one of the cams Iii?closes the limit switch LSI, the coil B is energized and a new cycle iscommenced.

If the switch H4 were opened, the abrading arm. would gothrough onecycle and halt in its upper position and a new cycle would be institutedby closing the push button I16. 7

If, at any time, the emergency switch I56 or the limit switch I58 or thehand switch I60 is opened, both of the drive motors are immediatelydeenergized While the brake or brakes associated with one or boththereof are energized to bring the entire mechanism to a sudden stop.

It will be understood while only one form of utensil has beenillustrated in the accompanying drawings, the abrading mechanism iscapable of adjustment to perform a finishing operation on substantiallyany size or shape pan, skillet or the like.

In any case, the finish on the utensil or vessel is uniform, precise,neat appearing and quickly accomplished so that there is a materialsaving in labor, and an improvement in the quality and appearance of thefinished product.

It will be understood that this invention is susceptible to modificationin order to adapt it to different usages and conditions and,accordingly, it is desired to comprehend such modifications within thisinvention as may fall within the scope of the appended claims.

I claim:

1. In an apparatus for finishing abrading one of the inner and outersurfaces of a pan-shaped workpiece, means for supporting and rotatingsaid workpiece, a movable arm, an abrading member yieldably carried onthe end of said arm to be moved thereby over said surface from thecenter of rotation of said workpiece outwardly, a joint in said arm,switch means responsive to a predetermined thrust on said abradingmember transverse to its direction of movement across said surface forbreaking said joint thereby permitting said abrading member to deflectaway from the surface being finished, motor means energizable to actuatesaid arm, and switch means responsive to the deflection of said abradingmember for de-energizing said motor means and for halting movement ofsaid arm.

2. In an apparatus for finishing one of the inner and outer surfaces ofrotating pan-shaped workpieces, means for supporting and rotating saidworkpiece, a movable arm; electric motor means energizable to actuatesaid arm, a finishing member yieldably carried on the end of said arm, ajoint in said arm adapted for being broken in response to apredetermined thrust on said finish- 'il'ig member lateral to itsdirection of movement,

electrical contacts in circuit with said motor means, and means carriedon said arm and adapted to be actuated by the breaking of said joint toactuate said contacts to de-energize said motor means.

3. In combination, in a machine for abrading a surface on a workpiece,means for supporting and rotating said workpiece on an axis passingthrough the center of said surface, an arm, abrading means carried onthe said arm comprising a supply of abrasive tape extending over the endof the arm, power means to actuate said arm to carry said abrading meansin a closed path a part of which is along and in engagement with thesaid surface and the other part of which is idle travel, means operabledurin the idle travel of said arm to feed said tape, and switch meansresponsive to the breakage of said tape to halt said power means.

4. In combination, in a machine for abrading a surface on a workpiece,means for supporting and rotating said workpiece on the axis of symmetryof the surface to be finished, an arm; abrading means carried on thesaid arm comprising a supply of abrasive tape extending over the end ofthe arm, takeup means to tension said tape,

power means energizable to actuate said arm to carry said abrading meansin a closed path a portion of which is along and in engagement withsurface being finished and the remainder of which is idle return travelalong a line spaced from the said surface, means to feed a predeterminedamount of said tape during the idle travel of said arm, and switch meansoperable automatically to de-energize said power means when said tapeloses tension.

5. In a machine for finish abrading a surface of a workpiece, means forsupporting and rotating a workpiece having a bottom and peripheral wallabout the axis of symmetry of the said'surface, an arm, a roller carriedon the end of said arm adjacent the surface to be finished, and abrasivecoated ribbon passing over said roller for abrading the said surface, apay-01f reel and a takeup reel for said ribbon carried on said arm andone thereof being spring urged to tension said ribbon and the otherthereof being intermittently actuated to feed a predetermined amount ofribbon over said roller, power means energizable to actuate said arm tocarry said roller over the surface being finished from the initialcontact at the said axis of the workpiece outwardly to the peripheralwall and along the peripheral wall, and switch means responsive to lossof tension in said ribbon for autorntically de-energizing said powermeans thus to bring said machine to a halt.

6. In a machine for finish abrading the inner surface of a rotatingpan-shaped workpiece, means to support and rotate said workpiece, amovable member adapted to have its end positioned against and movedacross said surface, an abrading means carried by said member to be,moved across said surface thereby, said abrading means comprising aresilient roller of a curvature in any plane greater than the curvatureof said inner surface in the same plane, a flexible abrading ribbonpassing over said roller, and ratchet wheel means operable automaticallyto feed said ribbon a predetermined amount after each movement acrosssaid surface to present a new abrading surface to each workpiece.

7. In a machine for finish abrading the inner surface of a rotatingpan-shaped workpiece, a turret, a plurality of rotatable work supportingchucks on said turret, means for indexing said turret to bring saidchucks consecutively into a work station, means operable to clampworkpieces in said chucks when in said work station and for rotatingsaid chucks, abrading mechanism including a movable arm adjacent saidwork station adapted to contact the inner surface ofthe workpiece at theaxis of rotation, an abrading end part on said arm, power means toactuate said arm to move said end part in a closed path 10 of which apart is the same shape as said inner surface from the initial contactpoint at the axis of rotation of the workpiece outwardly, a columnadjustably supported adjacent said turret, and means adjustablysupporting said abrading mechanism on said column.

WALTER I. KNAPP,

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